The present invention relates generally to the field of key cutting machines and, more specifically, to machines which cut teeth with non-orthogonal walls.
In the search for locks with greater security a number of improvements have been made to existing designs. Most existing security locks have pins and tumblers which are actuated by teeth which vary according to their depth and position. Recent locks, particularly those made popular by the MEDECO.RTM. Company, employ a third variable in that the teeth have angulated walls instead of the ninety-degree walls common to other locks.
These oblique walls create difficulty when angular bitted keys are duplicated. Current techniques require that the position, depth and angle of each tooth be measured, tabulated and then carefully reproduced. This process is both time-consuming and costly.
A number of solutions have been suggested to the problem of duplicating angular bitted keys. R. Oliver (U.S. Pat. No. 3,807,276) developed a lock key reproducing tool; however the locus of the key to be cut is not in the same plane as the cutter. N. Adler, et. al. (U.S. Pat. No. 3,457,831) provides a plunge activated cutter having angularly directed bits which has the disadvantage of requiring the withdrawal of a pin to set each cut. C. Sherman (U.S. Pat. No. 4,051,748) provides a key cutting machine for producing obliquely oriented bitting in which the pivot axis do not remain centered on the center of the cutter and the guide. Finally, N. Adler. et. al. (U.S. Pat. No. 3,457,832) provide a key cutter device in which the support posts prevent necessary rotation of the original key and the blank duplicate. For precision duplication of angular bitted keys the center of rotation of the angular tooth wall must be perpendicular to the radius of the cutting head at all times.